Characterization of Quasi-Keplerian Laboratory Plasmas

Characterization of Quasi-Keplerian, Differentially Rotating,
Free-Boundary Laboratory Plasmas
V. Valenzuela-Villaseca ,1,*,†
L. G. Suttle ,1
F. Suzuki-Vidal ,1,‡
J. W. D. Halliday ,1
S. Merlini ,1
D. R. Russell ,1
E. R. Tubman,1,∥
J. D. Hare ,1,§
J. P. Chittenden ,1
M. E. Koepke,2
E. G. Blackman ,3
and S. V. Lebedev 1
1
Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
2
Department of Physics, West Virginia University, Morgantown, West Virginia 26506, USA
3
Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
(Received 22 December 2021; accepted 29 March 2023; published 12 May 2023)
We present results from pulsed-power driven differentially rotating plasma experiments designed to
simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is injected
by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and
plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating
plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a
surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23 3 km=s. The
rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant κ2
∝ r−2.80.8
rad2
=s2
.
The plasma completes 0.5–2 full rotations in the experimental time frame (∼150 ns).
DOI: 10.1103/PhysRevLett.130.195101
Differentially rotating magnetohydrodynamical (MHD)
accretion flows orbiting a central object are ubiquitous in
the Universe [1,2]. The observational evidence of accretion
toward the central object requires angular momentum
transport to be far more efficient than can be provided
by kinematic viscosity. The enhancement is often modeled
as anomalous turbulent viscosity [3]. However, the
Rayleigh criterion guarantees the hydrodynamical stability
of Keplerian flows since they have a specific angular
momentum distribution lðrÞ increasing with radius as
l ¼ Ωr2
∝ r1=2
(r is the radial position and Ω the angular
frequency) [4]. Luckily, a magnetized flow with the same
rotation profile is unstable to the magnetorotational insta-
bility (MRI) [5–7], which is triggered when a differentially
rotating flow has an angular frequency stratification that
monotonically decreases with radius. Indeed, Keplerian
flows satisfy Ω ∝ r−3=2
.
Existing laboratory experiments use the Taylor-Couette
geometry to realize steady-state rotating MHD flows and
study instabilities, turbulence, and angular momentum
transport developing gradually over hundreds of rotation
periods. These experiments control the rotation profile from
the edges of the flow, either by spinning the vessel
containing a liquid (such as water or aqueous glycerol
[8], or sodium or gallium alloys under an external magnetic
field [9–15]), or by applying electrical currents from the
edge of Hall plasmas confined by permanent magnets at the
boundary [16–18].
In this Letter, we present results from the Rotating
Plasma Experiment (RPX), a novel pulsed-power driven
platform to study free-boundary differentially rotating
plasmas. The flow is quasi-Keplerian, i.e., dΩ=dr 0
and dl=dr 0, and allows the development of effects
with growth times comparable to the rotation period (e.g.,
the MRI [6]). The measured Rayleigh discriminant [19] is
κ2
∝ r−2.80.8
rad2
=s2
0. Thus, the flow rotation profile
meets the conditions to generate the MRI in a collisional
plasma. Additionally, the free-boundary design allows the
formation of axial plasma jets launched from the ends of the
plasma column, without the flow perturbations character-
istic of rigid wall containment [20–23]. The axial jet rotates
at a maximum velocity ≳20 km=s, undergoing between 0.5
and 2 full rotations for the duration of the experiment.
The experimental platform inertially drives a rotating
plasma by the oblique collision of multiple plasma jets [24],
which continuously inject both mass and angular momen-
tum to a rotating plasma column on the axis, as shown in
Fig. 1(a). On RPX, the colliding jets are ablation flows
accelerated by a cylindrical aluminium wire array (eight
40 μm wires, 16 mm diameter, 10 mm high) [25–27], as
shown in Fig. 1(b), driven on the MAGPIE pulsed-power
generator (1.4 MA peak electrical current, 240 ns rise time)
[28]. Aluminum plasma ablation flows have densities of a
few 1018 cm−3, and propagate with hypersonic velocities
4 × 104
− 1 × 105
m=s and characteristic temperature T ∼
10 eV (sonic Mach number Ms 5) [29–31]. Angular
momentum is introduced by the inward, off-axis trajectory
Published by the American Physical Society under the terms of
the Creative Commons Attribution 4.0 International license.
Further distribution of this work must maintain attribution to
the author(s) and the published article’s title, journal citation,
and DOI.
PHYSICAL REVIEW LETTERS 130, 195101 (2023)
Editors' Suggestion Featured in Physics
0031-9007=23=130(19)=195101(6) 195101-1 Published by the American Physical Society

of the ablation flows (described by the propagation angle
α), which is set by the ratio of radial-to-azimuthal magnetic
field components created by the applied current evaluated
at each wire. The azimuthal component Bθ ≈ 10 T is
mainly generated by the current passing through the wires,
whereas the radial component Br ≈ 2 T is introduced by
return posts slightly offset relative to the wires by an angle
φ0 ¼ 13° which carry the electrical current in the opposite
direction [Fig. 1(b)]. The experimental total time frame is
limited by the initial wire array mass [32], and corresponds
to 270 ns for the experiments presented in this Letter.
In each experiment, measurements of the temporal
evolution of the plasma density, temperature, and velocity
are obtained by using a multidiagnostic suite consisting
of self-emission (optical and XUV, 5 ns time resolution)
and laser probing [interferometry and optical Thomson
Scattering (TS)] [31,33,34].
Figure 1(c) shows one of the end-on optical self-
emission images (5 ns resolution, 600 nm) of the
ablation flows and the formation of the rotating plasma.
The ablation flows propagate inward, with an offset
propagation angle α ¼ 3° 1° [Fig. 1(c)]. As the ablation
flows propagate inward, their emission reduces due to
radiative cooling [35]. Considering the ablation velocity
Vab ¼ 6 × 104
m=s [29] and array radius r ¼ 8 × 10−3
m,
the specific angular momentum introduced by each wire
ablation is l ¼ rVab sinðαÞ ¼ 25 10 m2
=s. The 12 opti-
cal self-emission images obtained from each experiment
indicate that α can slightly vary by ∼1° between ablation
flows in the same experiment due to uneven current
distribution through the load.
The formation of the rotating plasma is shown in
Fig. 1(c), observed as a bright ring with a reduced intensity
on axis. This structure is consistent with a dense plasma
shell with a density depletion on axis sustained by a
centrifugal barrier. Thus, the plasma accumulates where
the centrifugal force is balanced by the inward ram pressure
of the ablation flows. This hollow structure is sustained
from 130 ns (formation time) to 210 ns.
Above the array, axial plasma outflows are observed by a
pair of four-frame, XUV cameras (100 μm pinhole, 1 μm
Mylar filter, 40 eV photon energy, 5 ns time resolution),
as shown in Fig. 1(d). A highly collimated jet is launched
by axial thermal and magnetic pressure gradients from the
formed rotating plasma column. By tracking the jet length
across different frames, the estimated axial velocity is
uz ¼ 100 20 km=s. The jet has a divergence angle of
3° 1°, and there is no visible development of typical
MHD instabilities of Z pinch plasmas [36,37], prior to
270 ns. The axial jet is surrounded by a plasma halo,
indicated in Fig. 1(d).
Measurements of the outflow’s electron density were
obtained using a Mach-Zehnder interferometer (532 nm
wavelength, 0.5 ns FWHM), with the probing beam
passing side on. The raw inteferogram was analyzed using
the MAGIC2 code [31,38] to construct a line-integrated
electron density
R
nedy map of the outflows, presented in
Fig. 2(a). Our coordinate system is such that the height
FIG. 1. Schematic diagrams of experimental setup and self-
emission images. (a) 3D schematic of inertially driven rotating
plasmas. (b) 3D schematic of experimental hardware. Axial
jets are not shown. (c) End-on optical self-emission image.
(d) Extreme ultraviolet (XUV) image of rotating plasma.
FIG. 2. (a) Line integrated electron density map. TS volumes
are overlaid in white circles. Additional arrows indicate the
scattering geometry. (b) Schematic TS setup and vector diagram.
(c) TS spectrum from outside the jet (plasma halo). Best fit is
shown in red. The spectrometer response is shown in gray. Fitting
parameters shown in gray box. (d) TS spectrum from inside the
jet. The characteristic double peak of the ion-acoustic wave
feature is observed.
195101-2

z ¼ 0 coincides with the upper surface of the top
anode disk.
A characterization of the density profile, velocity com-
ponents in the plane of rotation, and ion and electron
temperature of the outflows is presented in Fig. 3. A line-
integrated electron density lineout at the height of the TS
measurements [see Fig. 2(a)] is presented in Fig. 3(a). The
lineout was Abel inverted using a onion-peeling method
[39] independently on each side of the rotation axis,
and then the two sides are averaged, to obtain an electron
number density. The density profile of the plasma in this
region consists of an outer plasma halo at ∼0.2 ×
1018
cm−3
surrounding a hollow axial jet of maximum
density ∼0.5 × 1018 cm−3 on the shell and axial density
comparable to the halo.
Local measurements of velocity in the plane of rotation
and temperature are obtained using the TS diagnostic.
Scattered spectra are collected from 40 200 μm diameter
scattering volumes located across the collimated jet and the
surrounding plasma halo, as shown in Fig. 2(a). The
scattered light is collected by two linear arrays of
100 μm diameter optic fibers (labeled A and B), located
at 90° relative to the probing wave vector kin, as shown in
Fig. 2(b). Fits of the TS spectra [Figs. 2(c) and 2(d)] yield
measurements of the velocity components along the
scattering vectors kA ≡ kout;A − kin and kB ≡ kout;B−
kin, and the temperature Ti and the product of the average
charge state and electron temperature ZTe. This product is
decoupled using the non local thermodynamic equilibrium
code SpK [40,41]. The fit uses the electron density obtained
from interferometry shown in Fig. 3(b). From the velocity
components uA;B ≡ u · kA;B, the new components, along
and perpendicular to kin are calculated as
uk ¼ −
1
ffiffiffi
2
p ðuA þ uBÞ; u⊥ ¼
1
ffiffiffi
2
p ðuA − uBÞ: ð1Þ
The laser beam passes approximately through the rota-
tion axis with Fiber 5 viewing the position x ¼ 0 with an
estimated accuracy of 200 μm; however we cannot exclude
an offset of the jet in the perpendicular, y direction [(out of
plane in Fig. 2(a)]. If there is no offset of the probe beam
along y, the absolute values of the components ðuk; u⊥Þ
correspond exactly to the radial and rotation velocity
components ður; uθÞ. We show below that the interpretation
of the data is not sensitive to the offset of the beam relative
to the axial jet along the y axis.
The rotation velocity distribution is shown in Fig. 3(c).
Inside the jet, rotation is manifested as the change in sign in
the velocity about the axis [orange region in Fig. 3(c)]
exhibiting a maximum velocity of 23 3 km=s. The flow
velocity distribution is not symmetric about the jet axis.
Nonaxisymmetric modulations could be imprinted from the
discrete nature of the driver, i.e., the eight ablation flows.
Since the ablation geometry is steady, we do not expect the
nonaxisymmetric features to evolve significantly through-
out the experimental time frame. Figure 3(d) shows the
radial component of velocity. The plasma from the halo
propagates inward at a maximum velocity of 45 5 km=s,
before decelerating in the vicinity of the jet. We call this the
deceleration region [blue region in Fig. 3(d)]. This com-
ponent reaches a minimum inside of the jet, pointing along
kin, which indicates that the probe beam is misaligned with
the rotation axis.
Ion and electron temperature distributions obtained by
fitting the spectra from each fiber bundle independently are
shown in Fig. 3(e). At large radii (x 3 mm) Ti ≈ Te ¼
10 3 eV and gradually increase as the plasma approaches
the deceleration region. However, at the deceleration
region, the ion temperature of the inflowing plasma
increases by a factor of 5 over a length ∼1 mm, reaching
Ti ¼ 250 50 eV, whereas the electrons increase to
Te ≲ 20 eV. It is inferred that the inflow undergoes a
transonic deceleration: from a sonic Mach number Ms ∼ 3
at x ¼ 2.5 mm, to Ms ≲ 1 in the deceleration region. The
electron-ion equilibration time in the deceleration region
ν̄−1
eni ¼ 20 5 ns [42], equal to the transit time in this
region.
Inside the jet, Ti ranges between 50 15 eV and
100 20 eV, whereas Te ranges between ∼30 5 eV
FIG. 3. Plasma parameters. (a) Line-integrated electron density
lineout at the same height as the scattering volumes. Uncertainty
was estimated to be 20%. (b) Abel inverted electron density.
Left- and right-hand-side inversions (black lines) and averaged
inversion (dashed blue line). (c) Rotation velocity. (d) Radial
velocity. (e) Ion temperature. (d) Electron temperature. Down-
ward pointing arrows indicate the value is an upper constraint.
195101-3

and 50 10 eV, exhibiting a gradual increase toward the
axis. This increase Te is consistent with efficient electron-
ion thermal equilibration (ν̄−1
eni ¼ 18 5 ns). However,
radiative cooling prevents full equilibration as the radiative
cooling time is τcool ∼ 10 ns [43,44] (≈ν̄−1
eni), keeping the
electrons thermally uncoupled to the ions. The inferred
rotational Mach number Ms ∼ 0.8.
Further characterization of the velocity distribution is
presented. Figure 4(a) shows an end-on 2D velocity map
constructed from the TS measurements, where the positions
of the scattering volumes are translated according to an
impact parameter b, defined as the orthogonal distance
from the probing beam to the rotation axis (i.e., along y).
The scattering volumes are located at positions xi along the
x axis; thus the angular frequency at radius Ri ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
x2
i þ b2
p
is given by
ΩðRiÞ ¼
xiu⊥ − buk
R2
i
: ð2Þ
Figure 4(b) shows the calculated angular frequency
distributions for three values of the impact parameter: b ¼
0 mm (i.e., beam passing through the rotation axis),
b ¼ 0.1 mm, and b ¼ 0.3 mm. The result shows the
distribution does not significantly change with the impact
parameter. The angular frequency distribution for each
value of b is fitted independently either side of the axis
using a power law ∝ rγ
. For the case b ¼ 0, the point
closest to the axis was not considered. The variation of
values of b was used to find a range of values of γ indicated
in the figure. The Rayleigh discriminant can be calcu-
lated as κ2
≡r−3
dðr4
Ω2
Þ=dr∝ð4þ2γÞr2γ
¼r−2.80.8
0.
The physical meaning of this value of κ2
is twofold.
Firstly, its positive value implies that the flow is hydrody-
namically stable against axisymmetric perturbations. This
is because a linearly perturbed trajectory would oscillate
around an unperturbed one (having the same initial con-
ditions) with frequency κ, termed epicyclic frequency [45].
Nonaxisymmetric modes are unstable when lðrÞ ¼
constant, which is not satisfied by our plasma [see
Fig. 4(c)] [45,46]. Secondly, a magnetized, rotating flow
can be MRI unstable when dΩ=dr 0. It is explicit from
the definition of κ2
that both hydrostability and magneto-
rotational instability are satisfied simultaneously when
−2 γ 0. This case is called quasi-Keplerian rotation.
In that sense, κ2 fully characterizes the differential rotation
profile.
The viscous and resistive diffusion length scales, defined
such that the magnetic and fluid Reynolds numbers are of
order unity [42,47], are lη ∼ 70 μm and lν ∼ 0.5 μm
respectively. They are much smaller than both the plasma
length and diameter. In fact, by considering the diameter as
a relevant length, the fluid and magnetic Reynolds take
minimum characteristic values of Re ∼ 104
and Rm ∼ 30
meaning that dissipation is negligible in the experimental
time frame. Thus, in the presence of an external vertical
field (absent in these experiments), the MRI’s fastest
growing mode would develop on timescales jωmaxj−1
¼
jκ2
=4Ω − Ωj−1
¼ 150 100 ns, comparable to the orbital
period [45]. Therefore, these experiments demonstrate that
this free-boundary laboratory platform is able to produce
rotating flows with the correct profile and fluid conditions
to generate the linear MRI in a pulsed-power plasma. The
minimum external magnetic field required can be estimated
by imposing that the fastest growing mode can overcome
magnetic diffusion kz ∼ Ω=VA Ω=η (where VA is the
vertical Alfvén velocity) [6], which yields a minimum
external field in the range Bz ∼ 0.5–5 T, depending on the
plasma density. Moreover, the presence of axial jets might
help the instability growth if the axial expansion increases
the effective scale height more than it decreases the wave
number of perturbations, thereby allowing lower wave
numbers to become unstable during the duration of the
experiment.
In summary, we have presented an experimental char-
acterization of free-boundary rotating laboratory plasmas
which launch axial jets with a hollow density structure.
The measured rotation velocity profile corresponds to
quasi-Keplerian rotation with Rayleigh discriminant
FIG. 4. Rotation velocity distribution depending on TS beam
impact parameter b. (a) Diagram of the velocity map (black
arrows) of each TS volume (black circles). Example impact
parameter b ¼ 0.3 mm is shown. (b) Angular frequency distri-
bution. (c) Angular momentum distribution.
195101-4

κ2 ∝ r−2.80.8 0, indicating that the flow is hydrody-
namically stable but potentially MHD unstable. This is
limited to the mass per unit length of each wire, but it can
be increased by using wires of greater diameter.
Although current experiments are yet too short lived to
reach the MRI nonlinear regime and associated turbulent
angular momentum transport, they are a key initial step in
establishing a laboratory astrophysics platform for basic
investigations of rotating plasma flows. Observation of the
linear amplification of an externally applied, initial mag-
netic field by differential rotation in this platform, let alone
the fully developed MRI, would represent a novel proof-of-
principle measurement. These results are a first step toward
new efforts to generate and study the MRI, dynamo effects,
and collimation of jets in a single plasma experiment,
where effects such as radiative cooling are important. By
changing the wire material, the effect of radiative cooling
can be reduced, effectively suppressing magnetic diffusion,
and increasing both the plasma temperature, magnetic
Reynolds, and magnetic Prandtl numbers. The initial
conditions can be designed to produce a larger diameter
plasma, which would make it easier to diagnose [48].
Future experiments will study the magnetic field evolution
to investigate the existence of shear-flow magnetic dynamo
on RPX. Experiments on long-drive pulsed-power gener-
ators with microsecond rise times (e.g., Ref. [49]) could
sustain five to ten rotations, allowing the experiment to
enter the nonlinear, fully turbulent regime, and would allow
the assessment of the effect of azimuthal magnetic fields
which drive the slowly growing azimuthal MRI [50].
This work was supported in part by NNSA under
DOE Cooperative Agreements No. DE-SC0020434 and
No. DE-NA0003764. Vicente Valenzuela-Villaseca was
funded by the Imperial College President’s PhD
Scholarships and the Royal Astronomical Society. We
are grateful to the Mechanical Workshop at the Imperial
College Department of Physics, and in particular to David
Williams, for hardware fabrication. We thank Thomas
Varnish for writing some of the codes used in the analysis.
*
vv5425@princeton.edu
†
Current address: Department of Astrophysical Sciences,
Princeton University, Princeton, New Jersey 08544, USA.
‡
Current address: First Light Fusion Ltd., Yarnton,
Kidlington OX5 1QU, United Kingdom.
∥
Current address: Lawrence Livermore National Laboratory,
Livermore, California 94550, USA.
§
Current address: Plasma Science and Fusion Center,
Massachusetts Institute of Technology, Cambridge,
Massachusetts 02139, USA.
[1] J. E. Pringle, Accretion discs in astrophysics, Annu. Rev.
Astron. Astrophys. 19, 137 (1981).
[2] J. Frank, A. King, and D. Raine, Accretion Power
in Astrophysics, 3rd ed. (Cambridge University Press,
New York, 2002).
[3] N. I. Shakura and R. A. Sunyaev, Black holes in binary
systems. Observational appearance, Astron. Astrophys.
24, 337 (1973), https://ui.adsabs.harvard.edu/abs/1973A%
26A....24..337S/abstract.
[4] S. Chandrasekhar, Hydrodynamic and Hydromagnetic Sta-
bility, 1st ed. (Oxford University Press, New York, 1961).
[5] E. P. Velikhov, Stability of an ideally conducting liquid
flowing between cylinders rotating in a magnetic field, Sov.
Phys. JETP 36, 995 (1959), http://www.jetp.ras.ru/cgi-bin/
dn/e_009_05_0995.pdf.
[6] S. A. Balbus and J. F. Hawley, A powerful local shear
instability in weakly magnetized disks, Astrophys. J. 376,
214 (1991).
[7] J. Goodman and G. Xu, Parasitic instabilities in magne-
tized, differentially rotating disks, Astrophys. J. 432, 213
(1994).
[8] H. Ji, M. Burin, E. Schartman, and J. Goodman, Hydro-
dynamic turbulence cannot transport angular momentum
effectively in astrophysical disks, Nature (London) 444, 343
(2006).
[9] H. Ji, J. Goodman, and A. Kageyama, Magnetorotational
instability in a rotating liquid metal annulus, Mon. Not. R.
Astron. Soc. 325, L1 (2001).
[10] J. Goodman and H. Ji, Magnetorotational instability
of dissipative Couette flow, J. Fluid Mech. 462, 365
(2002).
[11] R. Hollerbach and G. Rüdiger, New Type of Magnetorota-
tional Instability in Cylindrical Taylor-Couette Flow, Phys.
Rev. Lett. 95, 124501 (2005).
[12] F. Stefani, T. Gundrum, G. Gerbeth, G. Rüdiger, M. Schultz,
J. Szklarski, and R. Hollerbach, Experimental Evidence for
Magnetorotational Instability in a Taylor-Couette Flow
Under the Influence of a Helical Magnetic Field, Phys.
Rev. Lett. 97, 184502 (2006).
[13] W. Liu, J. Goodman, I. Herron, and J. Hantao, Helical
magnetorotational instability in magnetized Taylor-Couette
flow, Phys. Rev. E 74, 056302 (2006).
[14] Y. Wang, E. P. Gilson, F. Ebrahimi, J. Goodman, K. J.
Caspary, H. W. Winarto, and H. Ji, Identification of a non-
axisymmetric mode in laboratory experiments searching for
standard magnetorotational instability, Nat. Commun. 13, 1
(2022).
[15] Y. Wang, E. P. Gilson, F. Ebrahimi, J. Goodman, and H. Ji,
Observation of Axisymmetric Standard Magnetorotational
Instability in the Laboratory, Phys. Rev. Lett. 129, 115001
(2022).
[16] C. Collins, N. Katz, J. Wallace, J. Jara-Almonte, I. Reese, E.
Zweibel, and C. B. Forest, Stirring Unmagnetized Plasma,
Phys. Rev. Lett. 108, 115001 (2012).
[17] K. Flanagan, J. Milhone, J. Egedal, D. Endrizzi, J. Olson,
E. E. Peterson, R. Sassella, and C. B. Forest, Weakly
Magnetized, Hall Dominated Plasma Couette Flow, Phys.
Rev. Lett. 125, 135001 (2020).
[18] J. Milhone, K. Flanagan, J. Egedal, D. Endrizzi, J. Olson,
E. E. Peterson, J. C. Wright, and C. B. Forest, Ion Heating
and Flow Driven by an Instability Found in Plasma Couette
Flow, Phys. Rev. Lett. 126, 185002 (2021).
[19] S. A. Balbus, On the behaviour of the magnetorotational
instability when the Rayleigh criterion is violated, Mon.
Not. R. Astron. Soc. 423, L50 (2012).
195101-5

[20] C. Gissinger, H. Ji, and J. Goodman, Instabilities in
magnetized spherical Couette flow, Phys. Rev. E 84,
026308 (2011).
[21] E. M. Edlund and H. Ji, Reynolds number scaling of the
influence of boundary layers on the global behavior of
laboratory quasi-Keplerian flows, Phys. Rev. E 92, 043005
(2015).
[22] S. A. Balbus, When is high Reynolds number shear flow not
turbulent?, J. Fluid Mech. 824, 1 (2017).
[23] K. J. Caspary, D. Choi, F. Ebrahimi, E. P. Gilson, J.
Goodman, and H. Ji, Effects of axial boundary conductivity
on a free Stewartson-Shercliff layer, Phys. Rev. E 97,
063110 (2018).
[24] D. D. Ryutov, Using intense lasers to simulate aspects of
accretion discs and outflows in astrophysics, Astrophys.
Space Sci. 336, 21 (2011).
[25] M. Bocchi, J. P. Chittenden, S. V. Lebedev, G. N. Hall, M.
Bennett, A. Frank, and E. G. Blackman, Numerical simu-
lations of Z-pinch experiments to create supersonic differ-
entially-rotating plasma flows, Astrophys. J. 767, 84 (2013).
[26] M. Bocchi, J. P. Chittenden, S. V. Lebedev, G. N. Hall, M.
Bennett, A. Frank, and E. G. Blackman, Numerical simu-
lations of Z-pinch experiments to create supersonic differ-
entially-rotating plasma flows, High Energy Density Phys.
9, 108 (2013).
[27] M. J. Bennett et al., Formation of radiatively cooled,
supersonically rotating, plasma flows in Z-pinch experi-
ments: Towards the development of an experimental plat-
form to study accretion disk physics in the laboratory, High
Energy Density Phys. 17, 63 (2015).
[28] I. H. Mitchell, J. M. Bayley, J. P. Chittenden, J. F. Worley,
a. E. Dangor, M. G. Haines, and P. Choi, A high impedance
mega-ampere generator for fiber z-pinch experiments, Rev.
Sci. Instrum. 67, 1533 (1996).
[29] A. J. Harvey-Thompson et al., Optical Thomson Scattering
Measurements of Plasma Parameters in the Ablation Stage of
Wire Array Z Pinches, Phys. Rev. Lett. 108, 145002 (2012).
[30] A. J. Harvey-Thompson et al., Optical Thomson scattering
measurements of cylindrical wire array parameters, Phys.
Plasmas 19, 056303 (2012).
[31] G. F. Swadling, S. V. Lebedev, N. Niasse, J. P. Chittenden,
G. N. Hall, F. Suzuki-Vidal, G. Burdiak, A. J. Harvey-
Thompson, S. N. Bland, P. De Grouchy, E. Khoory, L.
Pickworth, J. Skidmore, and L. Suttle, Oblique shock
structures formed during the ablation phase of aluminium
wire array z-pinches, Phys. Plasmas 20, 022705 (2013).
[32] S. V. Lebedev, F. N. Beg, S. N. Bland, J. P. Chittenden, A. E.
Dangor, M. G. Haines, S. A. Pikuz, and T. A. Shelkovenko,
Plasma formation and the implosion phase of wire array
z-pinch experiments, Laser Part. Beams 19, 355 (2001).
[33] G. F. Swadling et al., Diagnosing collisions of magnetized,
high energy density plasma flows using a combination of
collective Thomson scattering, Faraday rotation, and inter-
ferometry (invited), Rev. Sci. Instrum. 85, 11E502 (2014).
[34] L. G. Suttle, J. D. Hare, J. W. Halliday, S. Merlini, D. R.
Russell, E. R. Tubman, V. Valenzuela-Villaseca, W.
Rozmus, C. Bruulsema, and S. V. Lebedev, Collective
optical Thomson scattering in pulsed-power driven high
energy density physics experiments (invited), Rev. Sci.
Instrum. 92, 033542 (2021).
[35] S. V. Lebedev, A. Ciardi, D. J. Ampleford, S. N. Bland, S. C.
Bott, J. P. Chittenden, G. N. Hall, J. Rapley, C. Jennings, M.
Sherlock, A. Frank, and E. G. Blackman, Production of
radiatively cooled hypersonic plasma jets and links to
astrophysical jets, Plasma Phys. Controlled Fusion 47,
B465 (2005).
[36] S. C. Bott, S. V. Lebedev, D. J. Ampleford, S. N. Bland, J. P.
Chittenden, A. Ciardi, M. G. Haines, C. Jennings, M.
Sherlock, G. Hall, J. Rapley, F. N. Beg, and J. Palmer,
Dynamics of cylindrically converging precursor plasma
flow in wire-array Z -pinch experiments, Phys. Rev. E
74, 046403 (2006).
[37] F. Veloso, G. Muñoz-Cordovez, L. Donoso-Tapia, V.
Valenzuela-Villaseca, F. Suzuki-Vidal, G. Swadling, J.
Chittenden, M. Favre, and E. Wyndham, Ablation dynamics
in wire array Z-pinches under modifications on global
magnetic field topology, Phys. Plasmas 22, 072509 (2015).
[38] J. D. Hare, J. MacDonald, S. N. Bland, J. Dranczewski,
J. W. D. Halliday, S. V. Lebedev, L. G. Suttle, E. R. Tubman,
and W. Rozmus, Two-colour interferometry and Thomson
scattering measurements of a plasma gun, Plasma Phys.
Controlled Fusion 61, 085012 (2019).
[39] C. J. Dasch, One-dimensional tomography: A comparison
of Abel, onion-peeling, and filtered backprojection meth-
ods, Appl. Opt. 31, 1146 (1992).
[40] N.-P. L. Niasse, Development of a pseudo Non-LTE model
for Z-pinch simulations, Ph.D. thesis, Imperial College
London, 2011.
[41] J. D. Hare, High energy density magnetic reconnection
experiments in colliding carbon plasma flows, Ph.D. thesis,
Imperial College London, 2017.
[42] J. Huba, NRL Plasma Formulary, (Naval Research
Laboratory, Washington, DC 2016).
[43] F. Suzuki-Vidal et al., Bow shock fragmentation driven by a
thermal instability in laboratory astrophysics experiments,
Astrophys. J. 815, 96 (2015).
[44] D. R. Russell, Bow shock interaction experiments in a
magnetised collisional plasma, Ph.D. thesis, Imperial
College London, 2021.
[45] S. A. Balbus and J. F. Hawley, Instability, turbulence, and
enhanced transport in accretion disks, Rev. Mod. Phys. 70,
53 (1998).
[46] J. C. B. Papaloizou and J. E. Pringle, The dynamical stabil-
ity of differentially rotating discs with constant specific
angular momentum, Mon. Not. R. Astron. Soc. 208, 721
(1984).
[47] D. Ryutov, R. Drake, J. Kane, E. Liang, B. A. Remington,
and W. M. Wood-Vasey, Similarity criteria for the laboratory
simulation of supernova hydrodynamics, Astrophys. J. 518,
821 (1999).
[48] V. Valenzuela-Villaseca, Experimental study of magneto-
inertially driven, differentially rotating plasma flows,
Ph.D. thesis, Imperial College London, 2022.
[49] J. T. Banasek, T. G. Oliver, S. W. Cordaro, and S. C. Bott-
Suzuki, Free space Thomson scattering to study high energy
density shocks, Rev. Sci. Instrum. 92, 093503 (2021).
[50] G. Rüdiger, M. Gellert, M. Schultz, R. Hollerbach, and F.
Stefani, Astrophysical and experimental implications from
the magnetorotational instability of toroidal fields, Mon.
Not. R. Astron. Soc. 438, 271 (2014).
195101-6

Characterization of Quasi-Keplerian Laboratory Plasmas

Recomendados

Recomendados

Mais conteúdo relacionado

Semelhante a Characterization of Quasi-Keplerian Laboratory Plasmas

Semelhante a Characterization of Quasi-Keplerian Laboratory Plasmas (20)

Mais de Sérgio Sacani

Mais de Sérgio Sacani (20)

Último

Último (20)

Characterization of Quasi-Keplerian Laboratory Plasmas